<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package	Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license	http://framework.zend.com/license/new-bsd	 New BSD License
 */


/** Zend_Search_Lucene_Search_Weight */
require_once 'Zend/Search/Lucene/Search/Weight.php';


/**
 * @category   Zend
 * @package	Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license	http://framework.zend.com/license/new-bsd	 New BSD License
 */
class Zend_Search_Lucene_Search_Weight_MultiTerm extends Zend_Search_Lucene_Search_Weight
{
	/**
	 * IndexReader.
	 *
	 * @var Zend_Search_Lucene_Interface
	 */
	private $_reader;

	/**
	 * The query that this concerns.
	 *
	 * @var Zend_Search_Lucene_Search_Query
	 */
	private $_query;

	/**
	 * Query terms weights
	 * Array of Zend_Search_Lucene_Search_Weight_Term
	 *
	 * @var array
	 */
	private $_weights;


	/**
	 * Zend_Search_Lucene_Search_Weight_MultiTerm constructor
	 * query - the query that this concerns.
	 * reader - index reader
	 *
	 * @param Zend_Search_Lucene_Search_Query $query
	 * @param Zend_Search_Lucene_Interface	$reader
	 */
	public function __construct(Zend_Search_Lucene_Search_Query $query,
								Zend_Search_Lucene_Interface	$reader)
	{
		$this->_query   = $query;
		$this->_reader  = $reader;
		$this->_weights = array();

		$signs = $query->getSigns();

		foreach ($query->getTerms() as $id => $term) {
			if ($signs === null || $signs[$id] === null || $signs[$id]) {
				$this->_weights[$id] = new Zend_Search_Lucene_Search_Weight_Term($term, $query, $reader);
				$query->setWeight($id, $this->_weights[$id]);
			}
		}
	}


	/**
	 * The weight for this query
	 * Standard Weight::$_value is not used for boolean queries
	 *
	 * @return float
	 */
	public function getValue()
	{
		return $this->_query->getBoost();
	}


	/**
	 * The sum of squared weights of contained query clauses.
	 *
	 * @return float
	 */
	public function sumOfSquaredWeights()
	{
		$sum = 0;
		foreach ($this->_weights as $weight) {
			// sum sub weights
			$sum += $weight->sumOfSquaredWeights();
		}

		// boost each sub-weight
		$sum *= $this->_query->getBoost() * $this->_query->getBoost();

		// check for empty query (like '-something -another')
		if ($sum == 0) {
			$sum = 1.0;
		}
		return $sum;
	}


	/**
	 * Assigns the query normalization factor to this.
	 *
	 * @param float $queryNorm
	 */
	public function normalize($queryNorm)
	{
		// incorporate boost
		$queryNorm *= $this->_query->getBoost();

		foreach ($this->_weights as $weight) {
			$weight->normalize($queryNorm);
		}
	}
}


